Net Loss per Share - Schedule of Antidilutive Securities Excluded from the Computation of Diluted Net Loss per Share (Details) - shares
|
3 Months Ended |
Apr. 30, 2019 |
Apr. 30, 2018 |
| Stock options to purchase common stock | Class A Common Stock |
|
|
| Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] |
|
|
| Antidilutive securities excluded from computation of earnings per share (in shares) |
2,471,439
|
3,539,338
|
| Stock options to purchase common stock | Class B Common Stock |
|
|
| Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] |
|
|
| Antidilutive securities excluded from computation of earnings per share (in shares) |
5,700,441
|
9,001,291
|
| Unvested restricted stock units |
|
|
| Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] |
|
|
| Antidilutive securities excluded from computation of earnings per share (in shares) |
2,561,471
|
646,518
|
| Early exercised stock options |
|
|
| Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] |
|
|
| Antidilutive securities excluded from computation of earnings per share (in shares) |
47,550
|
234,646
|
| Shares underlying the conversion spread in the convertible senior notes |
|
|
| Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] |
|
|
| Antidilutive securities excluded from computation of earnings per share (in shares) |
1,945,081
|
0
|